Dielectric Properties of Calcium Copper Titanates (CaCu3Ti4O12) Synthesized by Solid State Reaction

The conventional solid-state reaction technique was used to obtain CaCu3Ti4O12 (CCTO) Ceramics. The crystal structure, microstructure and dielectric properties of polycrystalline CCTO samples sintered at different temperatures were investigated. X-ray diffraction (XRD) patterns showed no change in crystal structure phase of samples sintered at different temperatures. The SEM showed normal grain growth in CCTO samples sintered at 1090 C, while abnormal grain growth was observed in samples sintered at 1140C. The chemical composition of the calcined powder determined by EDS corresponds to CaCu3Ti4O12. Dielectric constant of CCTO ceramic sintered at 1090 C showed weak frequency dependence in the range of 100 Hz to 1 MHz, and gave a value of 104 measured at room temperature and 100 Hz. While the samples sintered at 1140C showed significant frequency dependence and gave a value of 105. The dielectric loss was about 0.3 for the sample sintered at 1090 C while it was close to 1 for the sample sintered at 1140 C.